The typical rotor for a rotary press has a die plate as well as a lower and upper punch guide for the lower and upper punches which interact with holes in the die plate. The rotor is driven by a suitable drive motor around a vertical axis, and the powdered material that is being filled by a filling device into the die holes, is compressed by the press punches. The compression occurs in at least one compression station which has an upper and lower compression roller that interact with the heads of the press punches. In the remaining rotary phases, the press punches are guided by suitable punch curves, among others for ejecting the pellets by the lower punches using appropriate control curves. Such rotors are known from U.S. Pat. No. 5,004,413, DE 101 59 114 A1, or DE 10 2004 040 163 B3, the entire contents of each of these references are incorporated herein by reference.
The distance between press punches, which are arranged in pairs on a partial circle on the rotor, is essentially determined by the diameter of the punch heads. The top side of the press punch heads with which the compression rollers interact is essentially standardized. Between the engagement lines on the punch heads there exists a not inconsiderable distance, which results in the fact that that an uneven transition of the compression roller occurs from one to the following punch. This causes a considerable noise emission to develop. In addition, this causes wear on the punch and the compression roller.
The objective of the invention is to reduce the unfavorable interaction between the compression roller and the punch head, and, with equal pressure holding time, to increase the space for the number of pressing stations on the partial circle, without increasing the expenditure for the apparatus for a press rotor.